DESCRIPTION (adapted from the application): Since its inception in 1988 the Energy Balance Core has provided services to investigators conducting research on energy metabolism in relation to health and disease. The Core features a state-of-the-art room calorimeter and force platform which facilitate accurate measurements of total energy expenditure, and assessments of daily activity and exercise. The Core has also extended its services to measure substrate oxidation as well as fitness and physical performance testing. We now aim to provide continued excellence in energy metabolism services and to enhance nutrition assessment services for investigators seeking to use body composition and diet assessment methodologies in their investigations. In order to emphasize these growing service capabilities the Core has been renamed the Energy Balance and Nutrition Assessment Core. Dr. Ming Sun joined the Core in 1990 and became its Director in 1991. His research interest has been in energy balance and obesity. He has extensive experience in applying computers and electronic instruments to biomedical research. Dr. Gordon Jensen joined the Core and became its Co-Director in 1998. His research interests are in nutrition screening and assessment of older persons in relation to functional status. He provides expertise in body composition and diet assessments. Other very important additions to the Core were Drs. Buchowski, Chen, and Eck-Clemens. Dr. Buchowski's research focuses on nutritional aspects of energy balance and physical activity in general, and particularly as they relate to sickle cell disease. Dr. Chen's interest is in energy balance in healthy and diseased humans as well as in developing and improving measuring techniques in energy expenditure, intake, and body composition. Dr. Eck-Clemens research examines diet assessment methodology and in particular bio-behavioral biases in self-reports of dietary intake in women.